THE LEUCOCYTES IN ORGANIC FUNCTIONS. 675 



nected with the vacuole, while this cavity serves as terminal for 

 all the mfoznuclear channels if such they are. 



Is the connection between this vacuole and the exterior of 

 the cell direct or indirect: i.e., through separate channels lead- 

 ing directly to the exterior or to those connected with the astro- 

 phere's system? That the communication is independent of 

 the latter is emphasized by the presence of granules in the 

 path of all canaliculi, as shown in Gulland's plate. A contin- 

 uous function depending upon an inflow of plasma would ob- 

 viously be in constant danger of arrest were the granular chan- 

 nels centripetal pathways. Again, in all leucocytes, acidophiles 

 as well as basophiles, the nucleus stains in the same manner, 

 the granules alone, as we have seen, showing variations in this 

 particular. The sanie may be said of the reticulum, for we 

 have seen, by the staining reactions, that the compounds com- 

 posing the granules are bathed in oxidizing substance. This 

 uniformity of nuclear and cellular fluids in the canaliculi sug- 

 gests the presence of a common mechanism one, indeed, which 

 must serve to eliminate its contents, judging from the fact al- 

 ready mentioned, that the size of the intracellular granules in- 

 creases in size outwardly, the largest granules being at or near 

 the surface. A common centrifugal canalicular system again 

 suggests the presence of a system common to all leucocytes, 

 whether phagocytic or not, for the introduction (not necessarily 

 of particles or other discernible agencies) of more or less liquid 

 or viscid bodies required by the cell for its own nutrition, or 

 connected with its own physiological functions: i.e., the elab- 

 oration of granules. The canaliculi serving only for the cen- 

 trifugal elimination of the latter, the centripetal paths must 

 penetrate to the vacuoles between the canaliculi, or "threads," 

 as already explained, and as shown in MetchnikofPs plate, 

 Fig. 5. We are evidently not dealing here with mere inclusion 

 or pseudopodial flowing around the germs, for the latter may 

 be seen to penetrate the cell between the granules, and, judg- 

 ing from Figs. 13, 14, 15, and 16, directly into the perinuclear 

 vacuole itself. 



Is the cell supplied with centripetal canaliculi in addition 

 to the centrifugal system which we believe to be represented 

 by the reticulum? The fact that micro-organisms can pene- 



43 



